The function \(\tau (x)\)  satisfying the relation (REF ) can be constructed in the following way. Let \(E(p_1,p_2)\)  be the prime form [1]}. Write
\(E(p_1,p_2)=\frac{E(z_1,z_2)}{\sqrt{{\rm d}z_1}\sqrt{{\rm d}z_2}},\) 
